﻿    <p>
      An <em>IfcPropertyListValue</em> defines a property that has several (numeric or
      descriptive) values assigned, these values are given by an ordered list. It defines a property - list value
      combination for which the property <em>Name</em>, an optional <em>Description</em>, the optional <em>ListValues</em> with measure
      type and optionally an <em>Unit</em> is given.
      An <em>IfcPropertyListValue</em> is a list of values. The order in which values appear is significant. 
      All list members shall be of the same type.
    </p>
    <p>
      The unit is handled by the <em>Unit</em> attribute, see Table 2 for an example of a list property:
    </p>
    <ul>
      <li>If the <em>Unit</em> attribute is not given, then the unit is already implied by the type of
      <em>IfcMeasureValue</em> or <em>IfcDerivedMeasureValue</em>. The associated unit can be found at the
      <em>IfcUnitAssignment</em> globally defined at the project level (<em>IfcProject.UnitsInContext</em>).
      </li>
      <li>If the <em>Unit</em> attribute is given, then the unit assigned by the <em>Unit</em> attribute overrides the
      globally assigned unit.
      </li>
    </ul>
    <blockquote class="note">
      NOTE&nbsp; An <em>IfcPropertyListValue</em> may be exchanged with no values assigned yet. In this case the
      <em>ListValues</em> are set to NIL.
    </blockquote>
<p>&nbsp;</p>
<blockquote>    
<table>
 <tr>
  <td>
   <table class="gridtable">
    <tr valign="top">
     <th width="15%">Name</td>
     <th width="30%">ListValues</td>
     <th width="25%">Type<br><span style="font-size:smaller">(through <em>IfcValue</em>)</span></td>
     <th width="30%">Unit</td>
    </tr>
    <tr>
     <td width="15%">ApplicableSizes</td>
     <td width="30%">1200</td>
     <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
     <td width="30%">-</td>
    </tr>
    <tr>
     <td width="15%">-</td>
     <td width="30%">1600</td>
     <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
     <td width="30%">-</td>
    </tr>
    <tr>
     <td width="15%">-</td>
     <td width="30%">2400</td>
     <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
     <td width="30%">-</td>
    </tr>
   </table>
  </td>
 </tr>
 <tr>
  <td><p class="table">Table 2 &mdash; List property with values, measure types and units</td>
 </tr>
</table>
</blockquote>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC2x2.
</blockquote>

<blockquote class="change-ifc2x4">
IFC4 CHANGE&nbsp; Attribute <em>ListValues</em> has been made OPTIONAL with upward compatibility for file based exchange.
</blockquote>